This invention relates to cylinder head gaskets. More particularly, the invention relates to improvements in fire ring design.
In the art of cylinder head gaskets, numerous practices have been employed for the purpose of achieving effective seals between cylinder heads and engine blocks with respect to combustion gases, lubricants, and cooling fluids circulated therethrough. Generally, clamping forces between the head and block are greater at the regions of the fastening members, typically bolts, than at points or regions away from the fastening members. Thus, there exists a pattern of gradients of seating loads over the gasketed areas, which produce undesirable distortions and strains in the cylinder bore areas.
Many prior art gaskets have utilized some form of compensating element to counteract such load distorting gradients, and to thereby attempt to effect a uniform or constant loading over the gasketed interface between cylinder head and engine block members. One common practice has involved the use of elastomeric sealants, which are utilized to build up areas over the gasket bodies between such bolted regions. However, where such gaskets have involved fire rings attached to boundaries of cylinder apertures, the latter procedures have proved ineffective to adequately compensate for load distortions, particularly where the bolt apertures are in relatively immediate vicinities of metallic fire rings.